What is Haller's apple moss?

Haller's apple moss

Mosses are green plants that often grow in a low, dense mat in moist, shady areas such as on the base of tree trunks, rocks, logs or soil. They do not have true roots to absorb nutrients and water. Instead, their stems are covered with tiny leaves that absorb water and nutrients like a sponge. Mosses use spores, not flowers or seeds, to reproduce themselves.

Mosses have two phases in their life cycle. The first phase is the gametophyte (or plant that produces gametes - male and female reproductive cells). It is an obvious, leafy green plant. Male and female gametes from this plant produce the second phase, the sporophyte (plant that produces spores). This plant consists of a thin stalk supporting a capsule filled with spores. When the spores are mature, the capsule opens and releases the spores, which blow away to start new gametophyte plants.

Haller's apple moss (Bartramia halleriana) is a small to medium-sized moss (4-14 cm tall) that is green to yellowish or brownish-green in colour. It is a monoicous plant, meaning that each plant has both male and female gamete-producing structures. In Canada , this species frequently produces a lot of spores.

Haller's apple moss grows on ledges, in crevices of shaded, forested cliffs, at the base of overhangs and where rock slides of acidic bedrock occur at lower elevations in the mountains. Extensive areas of seemingly suitable habitat are found in the mountains of western Canada , but the plant has not been found beyond these few sites. This suggests that factors other than suitable habitat may restrict its distribution.

Where does Haller's apple moss live?

In North America, Haller's apple moss is found only in western Canada . One location in Alberta (Jasper National Park) and two locations in eastern British Columbia (just west of Jasper National Park ) are currently known. It was also documented in Wood River, British Columbia, in 1826 by a botanist travelling with voyageurs. It has not been found there since that time.

Outside North America, Haller's apple moss occurs in Europe, Asia, southern South America, Hawaii, Australia and New Zealand.

In Canada, Haller's apple moss has been assessed as threatened by COSEWIC, and is protected under federal law by the Species at Risk Act. This is due to the small number of locations and population size. Alberta has ranked it as the highest category of conservation concern (S1). British Columbia has not ranked mosses, but this species would likely also be in the highest category. Worldwide, Haller's apple moss is not at risk.

What's so special about Haller's apple moss?

Thomas Drummond first discovered Haller's apple moss in Canada in 1826, while studying the plants and animals of the Canadian Rockies.

Defining an individual moss plant can be difficult because one clump can consist of many shoots, which originated from a single spore and are genetically identical. We consider a single, separate clump of moss to be one individual.

Haller's apple moss is at risk because there are only three small populations in Canada . Recent surveys at two of the sites documented 130 individuals (clumps), covering a total of 116 sq. cm. The total Canadian population is estimated to be less than 250 individuals.

Why is the Haller's apple moss in danger?

A forest fire

Conservation biologists have found that species with small populations are particularly at risk of being wiped out locally. Haller's apple moss occurs at only three small locations. It seems that only a limited, suitable habitat is available.

These small populations and suitable habitats may be threatened by any small disturbance, including development, fire or trampling. Small populations are also at greater risk because the population size fluctuates due to weather, for example, and because of genetic problems related to a small breeding population.

Haller's apple moss may be rare because it competes with other species for light, water and nutrients. It is frequently found growing with the closely related common apple moss (Bartramia pomiformis), which is much more abundant and widespread. Competition with common apple moss may be limiting the Haller's apple moss population size and distribution, but further study will be needed to evaluate this.

What is Parks Canada doing to help save the Haller's apple moss?

To protect Haller's apple moss, Parks Canada is actively involved in developing recovery actions and promoting research, public education and partnerships.

Research and Recovery

The Haller's Apple Moss Recovery Team, lead by Parks Canada, is preparing a recovery strategy and action plan for this species. Anticipated recovery and research activities include:

  • ensuring protection of the three currently known sites
  • developing a model of suitable habitat to guide additional surveys in eastern British Columbia and adjacent Alberta
  • monitoring population tendencies
  • researching the interaction of Haller's apple moss with common apple moss

Public education

As more is known about the biology and distribution of Haller's apple moss, Parks Canada interpreters, researchers and recovery team members can promote the importance of this special moss and its requirements. This may include programs, brochures, interpretive signs, Web sites and more.

Working with partners

Parks Canada staff from Jasper National Park and National Office are working with a variety of representatives on the Haller's Apple Moss Recovery Team, including:

  • British Columbia Ministry of Water, Land and Air Protection
  • University of Alberta, Devonian Botanic Garden

How can I help?

If you are visiting Jasper National Park of Canada:

  • Stay on designated paths to avoid disturbing this sensitive plant. 
  • Participate in park interpretive programs and activities to learn more about Haller's apple moss and how you can help.

If you are outside Jasper:

  • Try not to disturb sensitive habitats where Haller's apple moss may grow.